feat(model-adapter): add remote model selection

- Fetch and normalize OpenAI and Anthropic model lists through the proxy service.
- Add searchable multi-model selection with localized UI and persisted adapter mappings.
- Cover endpoint resolution, authentication, pagination, and response parsing.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/services/clientApi.js

@@ -161,3 +161,9 @@ export function getModelAdapterTestResults() {
     Call.ByName(`${PROXY_SERVICE_NAME}.GetModelAdapterTestResults`),
   );
 }
+
+export function fetchModelAdapterModels(payload) {
+  return withApiLogging("FetchModelAdapterModels", payload, () =>
+    Call.ByName(`${PROXY_SERVICE_NAME}.FetchModelAdapterModels`, payload),
+  );
+}